Liquid cooling system, and electronic apparatus having the same therein

ABSTRACT

In a cooling system of liquid type, dissolving a problem upon starting when applying a centrifugal pump therein, and being freely applicable into various kinds of electronic apparatuses, easily, for cooling a CPU in need of cooling thereof, which is mounted within a housing  100 , the system comprises: a cooling jacket  50 , a radiator  60  and a circulation pump, wherein the circulation pump is built up with a centrifugal pump, in which a rotor  730  having a plural number of blades formed in a centrifugal manner, a pump chamber  741  receiving the rotor in an inside thereof, and a field coil  712  of an electric motor for driving the rotor rotationally are formed into one body, and the pump chamber is disposed to located below the electric motor, thereby achieving the structure so that a liquid coolant fills up the pump chamber when stopping, in spite of the disposition of the circulation pump, thereby dissolving the problem of idling when starting.

BACKGROUND OF THE INVENTION

The present invention relates to an electronic apparatus, such as, apersonal computer, being so-called a desktop-type or a notebook-type, ora server, etc., and in particular, it relates to a liquid cooling systembeing able to cool down a heat-generation element mounted within aninside thereof, such as, a semiconductor integrated element, effectivelywith an aid of a liquid refrigerant or coolant, and further anelectronic apparatus having such the liquid cooling system therein.

In order to maintain a normal operation thereof, cooling is necessaryfor the heat-generation element, such as, the semiconductor IC element,being mounted within an electronic apparatus, including a personalcomputer, of called the desktop-type or the notebook-type, as well as, aserver, etc., and in particular, the heat-generation element, such as, aCPU (Central Processing Unit), as a representative one thereof, forexample. For this reason, conventionally, such the cooling is achievedgenerally by using a heat transfer element, being so-called a heat sinkthat is formed with fins thereon, as well as a fan, being provided forsending a cooling air thereto. However, small-sizing and highintegration of such the semiconductor IC element, such as theheat-generation element, in recent years, brings about localization ofthe heat generating at a portion thereof within the heat-generationelement, and also for this reason, attention comes to be paid onto acooling system of a liquid type of using the liquid coolant therein,such as a water, for example, being high in the cooling efficiencythereof, in the place of the conventional cooling system of anair-cooling type.

Namely, with the liquid cooling system of being high in the coolingefficiency thereof, which is used in the personal computer, of so-calledthe desktop-type or the notebook-type, and also the server, etc., as isknown from the following patent documents, for example, in general, anelement being so-called by a heat-receiving (or cooler) jacket ismounted on the surface of the heat-generating element, i.e., the CPU,directly, while conducting the liquid coolant within a flow passageformed within the heat-receiving jacket, so as to transmit or convey theheat generated from the CPU to the coolant flowing within the jacketmentioned above, thereby cooling down the heat-generating element withhigh efficiency. Further, in such the cooling system of theliquid-cooling type, normally, a heat cycle is made up with the coolerjacket, as the heat-receiving portion thereof, and in more detailsthereof, it comprises a circulation pump for circulating the liquidcoolant mentioned above within the cycle, so-called a radiator, being aheat-radiation portion for irradiating heat of the liquid coolantmentioned above into an outside, and further a coolant tank provided ina part of the cycle depending on the necessity thereof. And, those areconnected through a tube made of a metal and/or an elastic material,such as rubber or the like.

-   -   Patent Document 1: Japanese Patent Laying-Open No. 2003-304086        (2003);    -   Patent Document 2: Japanese Patent Laying-Open No. 2003-22148        (2003);    -   Patent Document 3: Japanese Patent Laying-Open No. 2002-182797        (2002);    -   Patent Document 4: Japanese Patent Laying-Open No. 2002-189536        (2002); and    -   Patent Document 5: Japanese Patent Laying-Open No. 2002-188876        (2002).

With the cooling system of the conventional arts mentioned above, inparticular, the cooling system of the liquid type, being high in thecooling efficiency, to be used in the personal computer, such as, of thedesktop type or the notebook type, and also the server, etc., normally,as a circulation pump to be provided in a part of the heat cycle thereoffor driving the liquid coolant, there is applied a pump of the so-calledcentrifugal type, due to the reasons that an amount of flow obtainedtherefrom it is large, that it is free from the deterioration due toabrasion and also small in the noises generated therefrom, since itincludes only a small portion sliding therein.

On the other hand, in spite of such the advantages mentioned above,however with such the pump of the centrifugal type mentioned above, dueto the structure and/or the principle thereof (i.e., being small incapacity of self-feeding, differing form the pump of the volume type,etc.), there is a necessity of filling up the liquid coolant, as a bodyto be driven therewith, within the pump chamber thereof, in particular,when starting up thereof. Namely, if there is not filled with asufficient amount of the liquid coolant as a body to be driven withinthe pump chamber thereof, when it starts up, the centrifugal pump makesso-called an idling, and depending upon the case, it results into aproblem that an electric motor for rotationally driving the pump burnsout, or a shaft thereof fastens, etc. For this reason, in the case whereapplying such the pump of the centrifugal type, it is located in a lowerportion of the liquid coolant in the disposition thereof.

However, in an electronic apparatus, including a personal computer, ofso-called the desktop-type or the notebook-type, and also a server,etc., accompanying the demands upon small-sizing of the equipment itselfin recent years, there is also strongly made a requirement of makingsmall the cooling system in the sized, to be used in this. For such thereasons, due to the high cooling efficiency thereof, attentions are paidupon the cooling system of the liquid type, in particular, with usingthe liquid coolant, such as, water, for example, and also applying thepump of the centrifugal type therein. However, due to the requirement ofsmall-sizing thereof, it is not necessarily in such a situation that thepump can satisfy such the requirement on the disposition or posturethereof mentioned above, fully.

SUMMARY OF THE INVENTION

Then, according to the present invention, being accomplished by takingthe drawbacks of the conventional arts mentioned above into theconsideration thereof, in more details, it is an object to provide anelectronic apparatus for dissolving such the problems coming up in thecooling system of the liquid type, applying the pump of the centrifugaltype therein; in particular, a cooling system of the structure beingapplicable into a personal computer, of so-called the desktop-type orthe notebook-type, and/or a server, etc., easily, and further, to anelectronic apparatus having such the cooling system therein.

According to the present invention, for accomplishing such the objectmentioned above, firstly, there is provided an electronic apparatus,installing a semiconductor element within a housing thereof, whichnecessitates cooling for maintaining normal operation thereof, in a partof the housing, and having a cooling system, within said housing or in apart thereof, said cooling system, comprising: a cooling jacket, beingthematically connected with said semiconductor element, for transmittingheat generated therein to a liquid coolant flowing within an insidethereof; a radiator for radiating the heat transmitted into the liquidcoolant within said cooling jacket into an outside of the apparatus; anda circulation pump for circulating said liquid coolant in a loop,including said cooling jacket and said radiator therein, wherein: saidcirculation pump is built up with a rotor formed with a plural number ofblades in a centrifugal manner, a pump chamber receiving said rotor, ina rotatable manner, within an inside thereof, and an electric motor forrotationally driving said rotor, being formed together into one body,and said pump chamber is located in a lower portion of said electricmotor.

Also, according to the present invention, in the electronic apparatus asdescribed in the above, it is preferable that said circulation pumpbuilding up said liquid cooling system has an inlet opening passage forguiding the liquid coolant into said pump chamber, and said inletopening passage is formed, extending from an upper portion of said pumpchamber to a lower portion thereof, and further that said inlet openingpassage is formed within an inside of a rotation shaft, for supportingsaid rotor, rotatabley, in said circulation pump. Also, according to thepresent invention, in the electronic apparatus as described in theabove, it is preferable that an outlet of the liquid coolant, coming outfrom said circulation pump building up said liquid cooling system, isformed at a position upper than the position of the blades of saidrotor, which is disposed within said pump chamber.

In addition thereof, according to the present invention, in theelectronic apparatus as described in the above, it is preferable thatsaid liquid cooling system further comprises a tank, which can supplythe liquid coolant therein, always irrespective of direction ofdisposition thereof, and an outlet of said tank is connected to an inletof said circulation pump.

Further, according to the present invention, for accomplishing theobject mentioned above, there is also provided a liquid cooling system,for cooling a semiconductor element generating heat therefrom,comprising: a cooling jacket, being thematically connected with saidsemiconductor element, for transmitting heat generated therein to aliquid coolant flowing within an inside thereof; a radiator forradiating the heat transmitted into the liquid coolant within saidcooling jacket into an outside of the apparatus; and a circulation pumpfor circulating said liquid coolant in a loop, including said coolingjacket and said radiator therein, wherein: said circulation pump isbuilt up with a rotor formed with a plural number of blades in acentrifugal manner, a pump chamber receiving said rotor, in a rotatablemanner, within an inside thereof, and an electric motor for rotationallydriving said rotor, being formed together into one body, and said pumpchamber is located in a lower portion of said electric motor.

Also, according to the present invention, in the liquid cooling systemas described in the above, it is preferable that said circulation pumpbuilding up said liquid cooling system has an inlet opening passage forguiding the liquid coolant into said pump chamber, and said inletopening passage is formed, extending from an upper portion of said pumpchamber to a lower portion thereof.

Also, according to the present invention, in the liquid cooling systemas described in the above, it is preferable that said inlet openingpassage is formed within an inside of a rotation shaft, for supportingsaid rotor, rotatabley, in said circulation pump, and further that anoutlet of the liquid coolant, coming out from said circulation pumpbuilding up said liquid cooling system, is formed at a position upperthan the position of the blades of said rotor, which is disposed withinsaid pump chamber.

In addition thereto, according to the present invention, in the liquidcooling system as described in the above, it is preferable that saidliquid cooling system further comprises a tank, which can supply theliquid coolant therein, always irrespective of direction of dispositionthereof, and an outlet of said tank is connected to an inlet of saidcirculation pump.

BRIEF DESCRIPTION OF THE VARIOUS VIEWS OF THE DRAWING

Those and other features, objects and advantages of the presentinvention will become more apparent from the following description whentaken in conjunction with the accompanying drawings wherein:

FIGS. 1(a) and 1(b) are an upper view and a vertical cross-section view,in particular, for showing the detailed structure of a circulation pumpin a cooling system, according to one embodiment of the presentinvention;

FIG. 2 is a perspective view for showing an example of the arrangementof each part partially exploded thereof, within a personal computer ofso-called the desktop type, for example;

FIG. 3 is a perspective view, in particular, for showing a coolingsystem within an electronic circuit portion, in the electronicapparatus, according to the one embodiment mentioned above;

FIGS. 4(a) and 4(b) are perspective views of a rotor in the circulationpump mentioned above, for showing the detailed structure thereof, seeingit from above and below, obliquely;

FIG. 5 is a vertical cross-section view for showing the structure of acirculation pump, according to other embodiment of the presentinvention;

FIG. 6 is a vertical cross-section view for showing the structure of thecirculation pump, which was shown in the above as one example thereof,but according to other embodiment of the present invention;

FIG. 7 is a perspective view for showing the other structure of theliquid cooling system in the electronic apparatus, according to otherembodiment of the present invention;

FIGS. 8(a) and 8(b) are perspective views, including the cross-sectionviews thereof, for showing a coolant tank to be used in the liquidcooling system, according to the other embodiment mentioned above, forstoring a liquid coolant therein, corresponding to various dispositionconditions thereof; and

FIGS. 9(a) and 9(b) are also perspective views, including thecross-section views thereof, for showing a coolant tank to be used inthe liquid cooling system, according to the other embodiment mentionedabove, for storing a liquid coolant therein, corresponding to variousdisposition conditions thereof.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, explanation will be given about the embodiments accordingto the present invention, in details thereof, by referring to thedrawings attached herewith.

First of all, FIG. 2 attached herewith shows an example of the entirestructure of an electronic apparatus having a liquid cooling systemtherein, according to one embodiment of the present invention. However,in this embodiment is shown a case, where the present invention isapplied into a main part or portion of a personal computer, such as, ofthe desktop type, for example.

As shown in the figure, the main portion of the desktop type personalcomputer comprises a housing 100, which is formed from a metal plateinto a cubic shape thereof, for example, and on a front panel portion101 thereof are provided various kinds of switches, including anelectric power switch therein, and indicator lamps, etc. Also, within aninside thereof is disposed a driver device 102, for driving variouskinds of external information recording medium, such as, a floppy disk,a CD, and a DVD, etc., so that it positions an opening thereof on thefront panel portion 101. Also, a reference numeral 103 in the figuredepicts a memory portion provided within the housing 100 mentionedabove, comprising a hard disk device, for example. And also, a referencenumeral 104 in the figure depicts a cover to be put on the housing 100mentioned above.

While on a rear side of the housing 100 is disposed an electroniccircuit portion 105, having a liquid cooling system according to thepresent invention, and a reference numeral 106 in the figure depicts anelectric power source portion for supplying from a commercial electricpower source, a desired electric power to each of the portions,including, the driver device 102, the memory portion 103, and theelectronic circuit portion 105 mentioned above.

Next, in FIG. 3 attached herewith is shown the electronic circuitportion 105 of the electronic apparatus, the brief structure of whichwas explained in the above; i.e., within the desktop type personalcomputer, in particular, mainly around a heat receiving jacket 50 formounting thereon a heat-generation element, such as, a CPU, as a main orprinciple structure thereof. However, in this embodiment, a chip 200 ofthe CPU, being the heat-generation element, is mounted on the lower sidesurface of the heat-receiving jacket 50 mentioned above, being incontact with, directly, therefore it is not illustrated on the figure,herein.

And, as is apparent from the figure, this electronic circuit portion 105comprises the above-mentioned heat-receiving (or cooling) jacket 50 formounting the CPU thereon, a radiator portion 60 for radiating heatgenerated from the CPU into an outside of the apparatus, a pump 70 forbuilding up a cooling system, and further flow passages are formed byconnecting tubes (conduits) 81, 82 . . . , being made of a metal, or anelastic material, such as a rubber or the like, being covered with ametal film, etc., on the outer surface thereof, so as to prevent theliquid coolant inside from leaking outside, for conducting a liquidcoolant (for example, a water, or a mixture of water with a so-calledanti-freezing solution, such as, propylene glycol, at a predeterminedratio thereof) to each of those portions building up the heat cycle.Also, in a part of the radiator portion 60 mentioned above, there areattached plate-like shaped fans 72, 72 . . . (in a plural number, suchas, three (3) pieces, in the present example), directing into an outsideof the apparatus, so as to blow an air onto a large number of metal thinpipes 61, 61 . . . as the constituent elements thereof, which will bementioned in more detail later, thereby radiating the heat transmittedfrom the heat receiving jacket 50 mentioned above, compulsively.Further, this heat-receiving (or cooling) jacket 50 is a plate-likemember, being made of a metal having high heat conductivity, such ascupper or the like, and being formed with a cooling passage within aninside thereof, to conduct or communicated the liquid coolant into thepassage thereof, thereby removing (moving) the heat generated from theCPU into the outside.

Following to the above, FIGS. 1(a) and 1(b) attached herewith show anupper view of the circulation pump 70 mentioned above, and at the sametime, a vertical cross-section view thereof. Namely, in this circulationpump 70, as shown in those figures, within an inside of a box (i.e., acase) 710 having a shape of quadrate or square in an outer configurationthereof, a field coil 712 building up a D-C motor, as an electric motorfor driving the pump rotationally, being molded around the peripherythereof by an insulating resin 713 in one body, and further a ring-likegutter or groove 714 is formed surrounding around the periphery of thefield coil 712, and into an inside thereof are disposed magnetelectrodes of the DC motor, which will be mentioned later. Also, on anupper surface of this square-shaped box (i.e., the case) 710, there isformed a suction port 720 of the liquid coolant extending into a centralportion thereof. This suction port 720 extends a little bit while beingbent downwards, at the central porting thereof. Further, as is apparentfrom the figures, at the central portion of the square-shaped box (i.e.,the case) 710, there is attached so-called an outer-ring shaft bearing715, in an inside thereof is inserted a rotation shaft of the rotor,which will be mentioned later.

On the other hand, the rotor 30 is built up with a plural number ofblades 731, 731 . . . (in the present example, six (6) pieces thereof)formed upon a disk-like member (in the figure, on the lower surfacethereof), as is apparent from FIGS. 1(a) and 1(b) and further FIGS. 4(a)and 4(b) attached herewith. Then, this rotor 730 comprises a ring-likeportion 732 extending upwards from an outer edge of that disk-likemember, and also on an interior wall surface of this ring-like portion732 is attached a ring-like shaped permanent magnet 733, beingpositioned (or magnetized) with the N pole and the S pole, alternately,as shown in the figure, for example. In addition thereto, at the centralportion of this rotor 730 made from the disk-like member, there isattached so-called a rotation shaft 734, which is made of a metal or aceramic and formed into a cylindrical shape, penetrating through thedisk-like member.

Namely, as is apparent from the figures mentioned above, the rotor 730is inserted into from the below in the figure, while fitting orinserting the rotation shaft 734 thereof into the outer-ring shaftbearing 715 of the box (i.e., the case) 710 and at the same timepositioning the ring-like portion 732 thereof within the groove 714,being ring-like in the outer configuration thereof, of the box (i.e.,the case) 710 mentioned above. Thereafter, on the lower surface of thebox (i.e., the case) 710, a lower portion box (i.e., a case) 740 isattached covering over the entire thereof, so that the plural number ofblades 731, 731 . . . of the rotor 730 are received within an insidethereof. Thus, between the upper surface of this lower box (i.e., thecase) 740 and the lower surface of the rotor mentioned above, a pumpchamber 741 is defined for suppressing the liquid coolant therein, andfurther, this pump chamber 741 is formed to be located in the lower sideof the electric motor portion for driving the pump rotationally. Also, areference numeral 742 depicts a discharge port for the liquid coolant,which is formed in a portion of the lower box (i.e., the case) 740mentioned above.

In this manner, in the circulation pump 70, the structure of which wasmentioned in the above, the flow passages for guiding the liquid coolantin an inside thereof are formed within an inside of the rotation shaft734, which supports the rotor 730, rotatably, and further on the lowerportion of this rotation shaft 734 (i.e., in an area where the blades731, 731 . . . are formed) are opened a plural number of penetratingholes 735. For this reason, when operating, the liquid coolant reachinginto the inside of the rotation shaft 734 of the rotor 730 is guidedinto an inside of the pump chamber 741 mentioned above, and iscompressed therein with the centrifugal force, by means of the pluralnumber of the blades 731, 731 . . . , and thereafter being dischargedfrom the discharge port 742 mentioned above.

On the other hand, within the calculation pump 70, when stopping theoperation thereof, the rotor 730 ends the rotation thereof, andaccompanying with this, the cooling liquid guided within the pumpchamber 742 is accumulated within an inside of the pump, includingbubbles and so on in a portion thereof. In that instance, as is apparentfrom FIGS. 4(a) and 4(b) mentioned above, in the vicinity of thedisk-like member, the penetrating holes 736, 736 . . . for use of babbleremoval are formed, respectively, on the lower surface of which thecentrifugal blades 731, 731 . . . , therefore, while a portion thereofmoves into an upper portion thereof through the rotation shaft 734mentioned above, the gas moves into an outside of the pump chamber 741,in more details, into an upper portion of the ring-like groove 714formed in the box (i.e., the case) 710, through the penetrating holes736, 736 . . . for use of bubble removal, even if the gas mixing thereinis separated from the liquid coolant. In other words, within thecirculation pump 70 having such the structure mentioned above, only theliquid coolant accumulates within the pump chamber 741, however the gasmixing in the liquid coolant never remains within the pump chamber 741,even when stopping.

For this reason, within the circulation pump 70 having such thestructure mentioned above, even when the operation is resumed (orstared) again, after temporal stoppage thereof, since only the liquidcoolant always fills up within the pump chamber 741, fully, whichreceives the blades 731 within the inside thereof, then the pump willnever run idle, therefore it is possible to obtain (re-start) the pumpoperation of the liquid coolant, with certainty. Namely, the circulationpump 70 mentioned above is installed within a part of the main body ofthe personal computer of the desktop type shown in FIG. 2 mentionedabove, and also it can perform the necessary pump operation, withcertainty, even in the case if it is disposed in any position within theliquid cooling system having such the structures shown in FIG. 3mentioned above.

Also, FIG. 5 attached herewith shows other embodiment of the circulationpump 70 mentioned above, and in this embodiment, the passage, in whichthe suction port 720′ of the liquid coolant is opened, is formedcovering over from a side surface of the box (i.e., the case) 710, up tothe central portion on the upper surface thereof, while being attachingon the wall surface and bent. Namely, with such the structure, upon whenstopping the operation of the circulation pump 70, the liquid coolant,which has been circulating up to that time, can easily stay in thesuction port 720′ formed to be bent, and also in that instance, inparticular, the liquid coolant flows into the rotation shaft 734 of therotor 730 mentioned above, and at the same time, the gaseous componentmixing into a portion thereof moves into an upper side of the suctionport 720′. Namely, in the similar manner to that of the embodimentmentioned above, the pump will never run idle, even when it is resumed(started), again, of the operation after the temporal stoppage thereof,since the liquid coolant fills up always within the pump chamber 741receiving the blades 731 within the inside thereof, thereby enabling thepump operation of the liquid coolant, with certainty.

Next, FIG. 6 attached herewith shows further other embodiment of thecirculation pump 70 mentioned in the above. In this example, differingfrom the embodiment mentioned above, first a portion 743 of the lowerportion box (i.e., the case) 740, building up the side wall of the pumpchamber 741 mentioned above, is extended upwards; thus, the opening ofthe discharge port 742 to the pump chamber 741 is disposed, so that theposition thereof comes to be upper than that of the centrifugal blades731, 731 . . . of the rotor 730.

Also, in the present embodiment, the suction port 720″ for the liquidcoolant are formed in one body, together with the discharge port 742mentioned above, on the lower box (i.e., the case) 740 building up thecirculation pump 70 mentioned above. Namely, as is apparent from thefigure, this suction port 720″, differing from the embodiment mentionedabove, is attached on the side surface of the circulation pump 70. And,in more details, this suction port 720″, as is apparent from the figure,reaches up to the lower surface of the lower box (i.e., the case) 740,after bending upwards, once, and thereafter, it extends on the lowersurface of the lower box (i.e., the case) up to the central portionthereof (i.e., the lower surface extending portion 721), and it opensdirecting from a lower wall surface 744 in vicinity of the centralportion of the rotor 730 mentioned above, into an inside of the pumpchamber 741. However, in this example, in the place of the hollowrotation shaft 734 mentioned above, a rod-like rotating shaft 734′ isattached at the central portion of the rotor 730, and on the other hand,on the side of the lower box (i.e., the case) 740 is attached aplate-like outer-ring shaft bearing 715′, into the hollow portionthereof the rod-like rotation shaft 734′ is inserted, thereby supportingthe rotor 730, rotatably.

With such the structure of the further other embodiment mentioned above,as is apparent from the figure, when the pump 70 stops, the rotor 730also stops the rotation thereof. And, accompanying with this, the liquidcoolant guided into the pump chamber 742 accumulates within the insideof the pump, containing bubbles and so on, in a part thereof. In thatinstance, as was mentioned above, since the position of the dischargeport 742 opening into the pump chamber 741 is arranged so that it comesto be lower than that the centrifugal blades 731, 731 . . . of therotor, and further since the suction port 720″ is opened at around thecentral portion of the pump chamber 741 from a lower wall surfacethereof, after being bent up and down, once, on the side surface of thepump, the gas is guided into the outside passing through the opening ofthe discharge port 742 disposed at the position above than thecentrifugal blades 731, 731 . . . of the rotor 730, even if the gasmixing therein is separated from the liquid coolant accumulated withinthe pump, therefore only the liquid coolant is accumulated within aninside of the pump chamber 741, which receives the centrifugal blades731, 731 . . . therein. In other words, during the time when stopping,no gas mixing into the liquid coolant is accumulated within the pumpchamber 741, thereby bringing about no idling run of the pump when it isre-started.

Following to the above, FIG. 7 attached herewith shows other liquidcooling system, according to further other embodiment of the presentinvention. However, in this embodiment, the numeral references beingsame to those shown in FIG. 3 mentioned above depict the constituentelements, which are same to those shown in the embodiment mentionedabove. Namely, as is apparent from those figures, in this further otherembodiment, between the radiator 60 and the circulation pump 70 buildingup the cooling system, a coolant tank 200 is further provided betweenthe radiator 60 and the circulation pump 70 mentioned above, building upthe cooling system, for the purpose of storing or accumulating theliquid coolant; e.g., the water or the mixture of the water and theanti-freezing solution, such as, propylene glycol or the like, in aninside thereof, to be circulated within the inside of the system.However, there may be cases where, this coolant tank 200 is locatedhorizontally, as is indicated by solid lines in the figure, orvertically, as is indicated by broken lines in the figure, for example,depending upon the restriction of the space within an inside thereof,for example, when it is disposed within the inside of the housing 100 ofthe desktop type personal computer shown in FIG. 2 in the above.

Then, this coolant tank 200 has the structure, as shown in FIGS. 8(a)and 8(b) attached herewith, wherein the coolant storage space definedwithin the inside thereof is divided into a plural number of spaces (forexample, three (3) spaces SP1, SP2 and SP3, in the present embodiment),with forming labylinth by combining partition walls 201, 202, 203 and204, each having about “L”-like cross-section shape. Also, a referencenumeral 205 in the figure indicates an inlet for the liquid coolantflowing into from the radiator 60 mentioned above, and 206 an outlet forthe liquid coolant flowing out into the circulation pump 70 mentionedabove. Further, reference numerals 206 and 207 indicate portions of thepartition walls 202 and 204, each having the “L”-like cross-section;thus, an opening portion that is formed at the position in the vicinityof an outer periphery of the tank.

In accordance with the coolant tank 200 having such the structuretherein, as is apparent from FIGS. 8(a) and 8(b) mentioned above, andfurther FIGS. 9(a) and 9(b) attached herewith, if a bubble flows intothe inlet 205 of the tank, mixing into a portion of the liquid coolantwhile the portion thereof leaks out through vaporization, etc., into anoutside thereof, during it circulates within the cooling system,however, only the liquid coolant, but excluding the bubble therefrom, isalways sent out from the outlet 205 to the circulation pump mentionedabove. Therefore, it is possible to protect the circulation pump,building up an important constituent element in the cooling system ofusing the liquid coolant therein, in particular, from the idling due tothe gas existing within the pump chamber 741 when it is started, andalso from the damage of the circulation pump in itself, depending on acase, with certainty; thereby, obtaining the electronic apparatus havingthe cooling system superior in the cooling capacity, which can beapplied into the personal computer, of so-called the desktop type or thenotebook-type, and also the server, etc.

Though the mentioning given in the above was made only about the oneexample of the case where the liquid cooling system of using the liquidcoolant therein according to the present invention is applied, inparticular, into the main part of the personal computer of so-called thedesk-top type, however the present invention can be also applied intothe personal computer of so-called the notebook type and the server,etc. However, in that case, an in particular, in the former case, itwould be obvious matter that, for the person stilled in the art, forexample, in particular, as the radiator portion 60 among the constituentelements thereof, a radiation plate, which is built up with a metalplate attached with a conduit made of a metal, is attached on the coverside thereof, in more details thereof, the reverse side surface of theliquid crystal display device in the place of that mentioned in theabove.

Namely, according to the present invention fully mentioned above, it ispossible to provide the liquid cooling system, being applicable into theelectronic apparatus, such as, the personal computers, of so-called thedesktop-type and the notebook-type, and further the server, etc.,easily, and having a high cooling efficiency with using the pumpsuitable for small-sizing thereof, and also the electronic apparatushaving such therein, thereby enabling to dissolve the problems at thetime of starting mentioned above, in particular, even when applying thecentrifugal pump therein.

The present invention may be embodied in other specific forms withoutdeparting from the spirit or essential feature or characteristicsthereof. The present embodiment(s) is/are therefore to be considered inall respects as illustrative and not restrictive, the scope of theinvention being indicated by the appended claims rather than by theforgoing description and range of equivalency of the claims aretherefore to be embraces therein.

1. An electronic apparatus, installing a semiconductor element within ahousing thereof, which necessitates cooling for maintaining normaloperation thereof, in a part of the housing, and having a coolingsystem, within said housing or in a part thereof, said cooling system,comprising: a cooling jacket, being thermally connected with saidsemiconductor element, for transmitting heat generated therein to aliquid coolant flowing within an inside thereof; a radiator forradiating the heat transmitted into the liquid coolant within saidcooling jacket into an outside of the apparatus; and a circulation pumpfor circulating said liquid coolant in a loop, including said coolingjacket and said radiator therein, wherein: said circulation pump isbuilt up with a rotor formed with a plural number of blades in acentrifugal manner, a pump chamber receiving said rotor, in a rotatablemanner, within an inside thereof, and an electric motor for rotationallydriving said rotor, being formed together into one body, and said pumpchamber is located in a lower portion of said electric motor.
 2. Theelectronic apparatus, as described in the claim 1, wherein saidcirculation pump building up said liquid cooling system has an inletopening passage for guiding the liquid coolant into said pump chamber,and said inlet opening passage is formed, extending from an upperportion of said pump chamber to a lower portion thereof.
 3. Theelectronic apparatus, as described in the claim 2, wherein said inletopening passage is formed within an inside of a rotation shaft, forsupporting said rotor, rotatabley, in said circulation pump.
 4. Theelectronic apparatus, as described in the claim 1, wherein an outlet ofthe liquid coolant, coming out from said circulation pump building upsaid liquid cooling system, is formed at a position upper than theposition of the blades of said rotor, which is disposed within said pumpchamber.
 5. The electronic apparatus, as described in the claim 1,wherein said liquid cooling system further comprises a tank, which cansupply the liquid coolant therein, always irrespective of direction ofdisposition thereof, and an outlet of said tank is connected to an inletof said circulation pump.
 6. A liquid cooling system, for cooling asemiconductor element generating heat therefrom, comprising: a coolingjacket, being thermally connected with said semiconductor element, fortransmitting heat generated therein to a liquid coolant flowing withinan inside thereof; a radiator for radiating the heat transmitted intothe liquid coolant within said cooling jacket into an outside of theapparatus; and a circulation pump for circulating said liquid coolant ina loop, including said cooling jacket and said radiator therein,wherein: said circulation pump is built up with a rotor formed with aplural number of blades in a centrifugal manner, a pump chamberreceiving said rotor, in a rotatable manner, within an inside thereof,and an electric motor for rotationally driving said rotor, being formedtogether into one body, and said pump chamber is located in a lowerportion of said electric motor.
 7. The liquid cooling system, asdescribed in the claim 6, wherein said circulation pump building up saidliquid cooling system has an inlet opening passage for guiding theliquid coolant into said pump chamber, and said inlet opening passage isformed, extending from an upper portion of said pump chamber to a lowerportion thereof.
 8. The liquid cooling system, as described in the claim7, wherein said inlet opening passage is formed within an inside of arotation shaft, for supporting said rotor, rotatabley, in saidcirculation pump.
 9. The liquid cooling system, as described in theclaim 6, wherein an outlet of the liquid coolant, coming out from saidcirculation pump building up said liquid cooling system, is formed at aposition upper than the position of the blades of said rotor, which isdisposed within said pump chamber.
 10. The liquid cooling system, asdescribed in the claim 6, wherein said liquid cooling system furthercomprises a tank, which can supply the liquid coolant therein, alwaysirrespective of direction of disposition thereof, and an outlet of saidtank is connected to an inlet of said circulation pump.